Nursing Elites

1. Which of the following is NOT a recognized mode of natural selection?

• A. Directional selection (favoring one extreme trait value on a spectrum)
• B. Disruptive selection (favoring both extreme trait values on a spectrum)
• C. Stabilizing selection (favoring the average trait value on a spectrum)
• D. Sexual selection (selection based on mate choice that influences reproductive success)

Correct answer: D

Rationale: A) Directional selection is a recognized mode of natural selection where one extreme trait value on a spectrum is favored over others, leading to a shift in the average trait value over time. B) Disruptive selection is a recognized mode of natural selection where both extreme trait values on a spectrum are favored over the average trait value, potentially causing the population to split into distinct groups. C) Stabilizing selection is a recognized mode of natural selection favoring the average trait value on a spectrum over extreme values, resulting in reduced genetic diversity. D) Sexual selection differs from traditional natural selection modes as it involves mate choice and competition for mates, not direct selection pressure on traits affecting survival and reproduction in the environment. Sexual selection can drive the evolution of traits enhancing an individual's attractiveness for mating purposes.

2. Which cells myelinate neurons in the PNS?

• A. Oligodendrocytes
• B. Astrocytes
• C. Schwann cells
• D. Microglia

Correct answer: C

Rationale: Schwann cells are the glial cells responsible for myelinating neurons in the peripheral nervous system (PNS). They form the myelin sheath around axons, which helps in the conduction of electrical impulses. Oligodendrocytes, on the other hand, myelinate neurons in the central nervous system (CNS). Astrocytes primarily provide support for neuronal function by regulating the chemical environment around neurons and maintaining the blood-brain barrier. Microglia are part of the immune response in the CNS, where they act as the resident macrophages, playing a role in immune surveillance and response to injury or disease. Therefore, the correct answer is Schwann cells (Choice C) as they specifically myelinate neurons in the PNS, differentiating them from the other cell types mentioned in the choices.

3. In the 18th century, women were more likely to die in childbirth compared to the 21st century. What is a possible explanation for why women are less likely to die in childbirth in the present age?

• A. Doctors are better equipped to perform cesarean sections.
• B. Doctors have more tools to monitor mothers during childbirth, enabling earlier detection of complications.
• C. Doctors practice good hand hygiene to prevent the transfer of germs and infections.
• D. All of the statements above provide reasonable explanations for the decrease in mortality during childbirth.

Correct answer: D

Rationale: All options are valid explanations for the decrease in maternal mortality during childbirth in modern times. Improved medical knowledge and technology have enabled doctors to perform cesarean sections more effectively, monitor mothers more closely for early detection of complications, and maintain better hygiene practices to reduce the risk of infections. Therefore, all the given statements collectively contribute to the reduction in maternal mortality rates in the 21st century.

4. Which part of the digestive system is primarily responsible for absorbing nutrients?

• A. Stomach
• B. Small intestine
• C. Esophagus
• D. Large intestine

Correct answer: B

Rationale: The small intestine is the primary site for nutrient absorption in the digestive system. It is lined with specialized cells that facilitate the absorption of nutrients such as carbohydrates, proteins, fats, vitamins, and minerals into the bloodstream for distribution throughout the body. While the stomach plays a role in digestion by breaking down food with acid and enzymes, the actual absorption of nutrients occurs mainly in the small intestine. The esophagus is responsible for transporting food from the mouth to the stomach, but it does not absorb nutrients. The large intestine primarily absorbs water and electrolytes, not nutrients.

5. Which of the following indicates the body's draining of clear fluid throughout the body to protect it from infection?

• A. Pulmonary Loop
• B. Systemic Loop
• C. Lymphatic System
• D. Immune System

Correct answer: C

Rationale: The correct answer is C, the Lymphatic System. The lymphatic system is responsible for draining clear fluid, known as lymph, throughout the body to protect it from infection. The other choices are incorrect because the pulmonary loop specifically refers to circulation between the heart and lungs, the systemic loop refers to circulation between the heart and the rest of the body, and the immune system is responsible for fighting infections and diseases rather than draining clear fluid.

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